Sinterable materials may be formed into shapes by various processes. Injection molding is a process wherein a material can be formed into a shape by forcing the material into a mold or die by fluidizing the material and injecting the fluidized material into the mold by applying a pressure to the fluidized material. The injection molding process facilitates a rapid and repeated forming of a plurality of articles having a consistent shape with close dimensional tolerances. The injection molding process minimizes the amount of shaping or machining that may be required to produce a finished article.
Many problems are encountered in the injection molding process for particulate materials which require high solids to binder ratio. Some of the problems which make it very difficult to make complex shapes of high solids to binder ratio compositions required in many sinterable materials (e.g. silicon nitride) are low green strength of the articles as molded, segregation of the binder from the particulate material during molding and poor green body flexibility.